Austrian Pat. No. 374 692 (which corresponds to U.S. patent application Ser. No. 510 458, filed July 1, 1983) describes an apparatus for the longitudinal adjustment of ski binding parts having a guide rail which is secured to a ski, which guide rail has two lateral guide edges each with a row of serrations thereon arranged between said guide edges and extend in the longitudinal direction of the apparatus. A locking member is associated with the toothed serrations and is under the influence of at least one compression spring which is supported at its end remote from the locking member on a guide plate which is guided on the guide rail and carries the heel holder thereon and which--viewed from the side--has approximately an upwardly open U-shaped cross section, whereby the crosswise extending web which connects the two legs has locking teeth thereon. One leg of the locking member lies in this apparatus under the influence of the compression spring on an inwardly projecting shoulder of the guide plate, and the other leg is lockable in the lifted position of the locking member, thus when the locking teeth are disengaged from the toothed bars.
It has been found in this apparatus that in practice the adjusting of the heel holder, which must be carried out very often in a rental ski, does not always occur with the necessary caution. The screw driver which is used for the adjustment is namely often applied with such force and thereafter swung upwardly in a vertical plane, that damage to the sensitive teeth of the toothed serrations occurs. This damage can at times be so great that the teeth on the locking member can be inserted only with great difficulty into the toothed serrations or that the teeth of the toothed serrations are deformed such that they no longer can reliably hold the locking member, which then during the downhill skiing jumps out of the toothed serrations.
It has furthermore been suggested to equip the heel holder itself with an apparatus to facilitate its longitudinal adjustment (see French Pat. No. 2 451 756). The guide rail is in this apparatus provided with two rows of holes, into two holes in each row extend two projections of a locking member, urged under the influence of a helical spring and against the guide rail in the locked position of the apparatus. The locking member is supported, when the ski shoe is not inserted, on a downwardly projecting wall of the housing of the heel holder. It is constantly coupled with an approximately U-shaped wire bar, the bight portion of which, which extends in transverse direction with respect to the guide rail, is stored in a recess of the heel holder.
If the heel holder is to be adjusted along the length of the guide rail, then the wire bar and thus the locking member are lifted by means of a special tool in the form of a screw driver having two grooves therein arranged in the narrow-side surfaces of the blade and which extend inwardly of the plate toward the axis of the screw driver, by swinging the screw driver through a 90.degree. angle. The heel holder can thereafter be moved along the length of the guide rail.
If the desired position of the heel holder is achieved, the screw driver is swung back through the 90.degree. angle and is thereafter pulled out of the wire bar. This causes, due to the helical spring, the projections on the locking member to extend into the holes of the guide rail. This embodiment has the disadvantage that for adjusting the locking member, a specially constructed tool must be used. Furthermore, the tool must, during the adjusting operation, remain in engagement with the binding part, which occupies one hand of the installer for this purpose and only the other hand of the installer is available for other adjusting operations.
The purpose of the invention is to provide a heel holder of the abovementioned type in which during a longer use and repeated adjustment, no damage to the toothed serrations on the guide rail can occur, whereby for the adjusting operation itself only a commercially available screw driver is needed.
This purpose is inventively attained by arranging a guard plate below the locking member, which guard plate covers mainly the section of the serrations or the like, which is opposite the free end area of the locking member. With this the mentioned section cannot be damaged, not even in the case of a rough treatment by the applied screw driver.
In order to assure a snug bearing of the guard plate on the guide rail and in order to prevent a bending of the same even when the locking member is swung up by the screw driver, the invention provides that the guard plate, for example by means of upwardly bent sections which have slotted holes therein, is pivotally supported for movement about a transverse axis which consists for example of two coaxial axles on the locking member and is supported movably with respect thereto to a certain degree. It is thereby advantageous if the longitudinal axis of the slotted holes defines with the vertical plane an angle of up to 25.degree., preferably an angle of 15.degree..
It would actually be conceivable to extend the free end area of the locking member and to arrange the guard plate only under the tail end area of the locking member. This, however, could possibly lead to a bending of the locking member. For this reason the invention suggests a further development, namely, that the guard plate has a recess in its center area, which recess is designated for passage of the section of the locking member which has the teeth thereon.
A modification of the last-disclosed embodiment is characterized by a guard plate which is U-shaped in the top view being hingedly connected to the locking member by means of two laterally spaced arms which extend in longitudinal direction of the heel holder toward the spring. This modification brings about a certain saving of weight of the heel holder.
According to a further characteristic of the invention, the guard plate has in the section which follows the free end at least one, preferably two ribs which extend in transverse direction and which are constructed for example as upstanding bulges. This characteristic prevents any kind of sliding off of the screw driver from the guard plate in direction toward the teeth.
In order to thereby make easier the applying of the screw driver to the guard plate and to prevent a backward sliding off of the screw driver, the invention provides further that the rib which is adjacent to the free end of the guard plate is lower than the other rib which is farther from the end.